Hello french-hair, Some time ago, John posted on this point. He said that hair tends to get caught/snagged in cotton fibers, satin or silk does not affect it. The result of using cotton pillow slips can be hair -loss from your system. You should apply liquid knot -sealer very thinly and sparingly to the underside of you system when you first get it. This also helps to avoid hair shedding.
Hope that helps, Paul.